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This project carries out a scientific research and emotional development about outstanding women scientists .


Women with conscience in science.

Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.

Marie Curie

This project carries out scientific research and emotional development to find out more about outstanding women scientists. Through a journey in time, they will help us discover more about the mystery qualities of life, sharing their values of effort, dedication and concentration.

Women with conscience in science.


Be less curious

about people and more curious about ideas.


20th century

Fields: Physics, Chemistry

Born: 1867 in Warsaw (Poland)
Death: 1934 in Passy (France)
Nobel Prizes in Physics in 1903 and Chemistery in 1911

Main achievements: Development of the theory of radioactivity (a term that she coined), of techniques for isolating radioactive isotopes, and discovery of two elements, polonium and radium.
Publications: List on Google Scholar

Marie Curie was a Polish-born physicist and chemist and one of the most famous scientists of her time. Together with her husband Pierre, she was awarded the Nobel Prize in 1903, and she went on to win another in 1911. Marie Sklodowska was born in Warsaw on 7 November 1867, the daughter of a teacher. In 1891, she went to Paris to study physics and mathematics at the Sorbonne where she met Pierre Curie, professor of the School of Physics. They were married in 1895. The Curies worked together investigating radioactivity, building on the work of the German physicist Roentgen and the French physicist Becquerel. In July 1898, the Curies announced the discovery of a new chemical element, polonium.

At the end of the year, they announced the discovery of another, radium. The Curies, along with Becquerel, were awarded the Nobel Prize for Physics in 1903. Pierre's life was cut short in 1906 when he was knocked down and killed by a carriage. Marie took over his teaching post, becoming the first woman to teach at the Sorbonne, and devoted herself to continuing the work that they had begun together. She received a second Nobel Prize, for Chemistry, in 1911.

The Curie's research was crucial in the development of x-rays in surgery. During World War One Curie helped to equip ambulances with x-ray equipment, which she herself drove to the front lines. The International Red Cross made her head of its radiological service and she held training courses for medical orderlies and doctors in the new techniques. Despite her success, Marie continued to face great opposition from male scientists in France, and she never received significant financial benefits from her work. By the late 1920s her health was beginning to deteriorate.

She died on 4 July 1934 from leukaemia, caused by exposure to high-energy radiation from her research. The Curies' eldest daughter Irene Joliot-Curie was herself a scientist and winner of the Nobel Prize for Chemistry.

Source: BBC

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Life is a chemical process.”

Antoine Lavoisier


18th century

Fields: Chemistry

Born: 1758 in Montbrison (France)
Death: 1836 in Paris (France)

Main achievements: The Lavoisiers rebuilt the field of chemistry.

Marie-Anne Pierrette Paulze Lavoisier was a French chemist and noble. She was the wife of Antoine Lavoisier and acted as his laboratory companion and contributed to his work.

Her father,Jacques Paulze, worked primarily as a parliamentary lawyer and financier. Most of his income came from running the Ferme Générale (the General Farm) which was a private consortium of financiers who paid the French monarchy for the privilege of collecting certain taxes. Her mother, Claudine Thoynet Paulze, died in 1761, leaving behind not only Marie-Anne, then aged 3 only, but two other sons. After her mother’s death Paulze was placed in a convent where she received her formal education.

At the age of thirteen Paulze received a marriage proposal from the 50-year-old Count d'Amerval. Jacques Paulze tried to object to the union, but received threats about losing his job with the Ferme Générale. To indirectly thwart the marriage, Jacques Paulze made an offer to one of his colleagues to ask for his daughter’s hand instead. This colleague was Antoine Lavoisier, a French nobleman and scientist. Lavoisier accepted the proposition, and he and Marie-Anne were married on 16 December 1771. Lavoisier was about 28, while Marie-Anne was about 13.

Lavoisier continued to work for the Ferme-Générale but in 1775 was appointed gunpowder administrator, leading the couple to settle down at the Arsenal in Paris. Here, Lavoisier’s interest in chemistry blossomed having previously trained at the chemical laboratory of Guillaume François Rouelle, and, with the financial security provided by both his and Paulze’s family, as well as his various titles and other business ventures, he was able to construct a state-of-the-art chemistry laboratory. Paulze soon became interested in his scientific research and began to actively participate in her husband's laboratory work.

As her interest developed, she received formal training in the field from Jean Baptiste Michel Bucquet and Philippe Gingembre, both of whom were Lavoisier’s colleagues at the time. The Lavoisiers spent most of their time together in the laboratory, working as a team conducting research on many fronts. She also assisted him by translating documents about chemistry from English to French. In fact, the majority of the research effort put forth in the laboratory was actually a joint effort between Paulze and her husband, with Paulze mainly playing the role of laboratory assistant.

Paulze accompanied Lavoisier in his lab during the day, making entries into his lab notebooks and sketching diagrams of his experimental designs. The training she had received from the painter Jacques-Louis David allowed her to accurately and precisely draw experimental apparatuses, which ultimately helped many of Lavoisier’s contemporaries to understand his methods and results. Furthermore, she served as the editor of his reports. Together, the Lavoisiers rebuilt the field of chemistry, which had its roots in alchemy and at the time was a convoluted science dominated by George Stahl’s theory of phlogiston.

In the eighteenth century the idea of phlogiston (a fire-like element which is gained or released during a material’s combustion) was used to describe the apparent property changes that substances exhibited when burned. Paulze, being a master in the English, Latin and French language, was able to translate various works about phlogiston into French for her husband to read. Perhaps her most important translation was that of Richard Kirwan's 'Essay on Phlogiston and the Constitution of Acids', which she both translated and critiqued, adding footnotes as she went along and pointing out errors in the chemistry made throughout the paper. She also translated works by Joseph Priestley, Henry Cavendish, and others for Lavoisier’s personal use. This was an invaluable service to Lavoisier, who relied on Paulze’s translation of foreign works to keep abreast of current developments in chemistry. In the case of phlogiston, it was Paulze’s translation that convinced him the idea was incorrect, ultimately leading to his studies of combustion and his discovery of oxygen gas.

Paulze was also instrumental in the 1789 publication of Lavoisier’s Elementary Treatise on Chemistry, which presented a unified view of chemistry as a field. This work proved pivotal in the progression of chemistry, as it presented the idea of conservation of mass as well as a list of elements and a new system for chemical nomenclature. Paulze contributed thirteen drawings that showed all the laboratory instrumentation and equipment used by the Lavoisiers in their experiments. She also kept strict records of the procedures followed, lending validity to the findings Lavoisier published.

Before her death, Paulze was able to recover nearly all of Lavoisier’s notebooks and chemical apparatuses, most of which survive in a collection at Cornell University, the largest of its kind outside of Europe. The year she died, a book was published, showing that Marie-Anne had a rich theological library with books which included versions of The Bible, St. Augustine's Confessions, Jacques Saurin's Discours sur la Bible, Pierre Nicole's Essais de Morale, Blaise Pascal's Lettres provinciales, Louis Bourdaloue's Sermons, Thomas à Kempis's De Imitatione Christi, etc.

Source: Wikipedia

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Discipline gives you

the freedom
to be creative.

Marguerite PEREY

20th century

Fields: Physics, Chemistry

Born : 1909 in Villemomble, Seine-Saint-Denis (France)
Death: 1975 in Louveciennes, Yvelines (France)

Main achievements: Francium discovery

Marguerite Catherine Perey was a French physicist and a student of Marie Curie. In 1939, Perey discovered the element francium by purifying samples of lanthanum that contained actinium. In 1962, she was the first woman to be elected to the French Académie des Sciences, an honor denied to her mentor Curie. Perey died of cancer in 1975.

Perey was born in 1909 in Villemomble, France, just outside Paris where the Curie's Radium Institute was located. Although she hoped to study medicine, the death of her father left the family in financial difficulties.

Perey earned a chemistry diploma from Paris' Technical School of Women's Education in 1929; while not a "degree", it did qualify her to work as a chemistry technician. At the age of 19, she interviewed for a job with Marie Curie at Curie's Radium Institute in Paris, France, and was hired. Marie Curie took on a mentoring role to Perey, taking her on as her personal assistant.

Under Marie Curie's guidance at the Radium Institute, Perey learned how to isolate and purify radioactive elements, focusing on the chemical element actinium (discovered in Curie's laboratory in 1899 by chemist André-Louis Debierne). Perey spent a decade sifting out actinium from all the other components of uranium ore, which Curie then used in her study of the decay of the element. Marie Curie died of aplastic anemia only five years after Perey began working with her, but Perey and Debierne continued their research on actinium and Perey was promoted to radiochemist.

In 1935, Perey read a paper by American scientists claiming to have discovered a type of radiation called beta particles being emitted by actinium and was skeptical because the reported energy of the beta particles didn't seem to match actinium. She decided to investigate for herself, theorizing that actinium was decaying into another element (a daughter atom) and that the observed beta particles were actually coming from that daughter atom. She confirmed this by isolating extremely pure actinium and studying its radiation very quickly; she detected a small amount of alpha radiation, a type of radiation that involves the loss of protons and therefore changes an atom's identity. Loss of an alpha particle (consisting of 2 protons and 2 neutrons) would turn actinium (element 89, with 89 protons) into the theorized but never-before-seen element 87. Perey named the element francium, after her home country, and it joined the other alkali metals in Group 1 of the periodic table of elements.

Perey received a grant to study at Paris' Sorbonne, but because she didn't have a bachelor's degree, the Sorbonne required her to take courses and obtain the equivalent of a B.S. to fulfill their PhD program requirements before she could earn her doctorate. She graduated from the Sorbonne in 1946 with a Doctorate of Physics. After obtaining her PhD, Perey returned to the Radium Institute as a senior scientist and worked there until 1949.

Perey was made the head of the department of nuclear chemistry at the University of Strasbourg in 1949, where she developed the University's radiochemistry and nuclear chemistry program and continued her work on francium. She founded a laboratory that in 1958 became the Laboratory of Nuclear Chemistry in the Center for Nuclear Research, for which she served as director. She also served as a member of the Atomic Weights Commission from 1950 to 1963.

Ironically Perey hoped that francium would help diagnose cancer, but in fact it itself was carcinogenic, and Perey developed bone cancer which eventually killed her. Perey died on May 13, 1975 (age 65). She is credited with championing better safety measures for scientists working with radiation.

Perey's archives with materials dating from 1929 to 1975 were left at the Université Louis Pasteur in Strasbourg. They include laboratory notebooks, course materials from her work as professor of nuclear chemistry, papers from her laboratory directorship, and publications. All documents are now currently held at the Archives départamentales du Bas-Rhin (Departamental archives of the Bas-Rhin).

Perey was elected to the French Academy of Sciences in 1962, making her the first woman elected to the Institut de France. Although a significant step, her election as a "corresponding member" rather than a full member came with limited privileges.

The French Academy of Science Wilde Prize (1950)
The French Academy of Science Le Conte Prize (1960)
The City of Paris Science Grand Prize (1960)[3]
Officier of the Légion d'Honneur (1960)
Grand Prix de la Ville de Paris (1960)
Elected correspondante of the Académie des Sciences (Paris, 1962). First woman to be elected to the Académie since its founding in 1666.
Lavoisier Prize of the Académie des Sciences (1964)
Silver Medal of the Société Chimique de France (1964)
Commandeur of the Ordre National du Mérite (1974)

Source: Wikipedia

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...not accidental, but the result of a long search!


20th century

Fields: Chemistry

Born: 1896 in Wesel (Germany)
Death: 1978 in Bad Neuenahr (Germany)

Main achievements: The first to mention the idea of nuclear fission (1934).

Ida Noddack, born Ida Tacke, was a German chemist and physicist. She was the first to mention the idea of nuclear fission in 1934. With her husband Walter Noddack she discovered element 75, rhenium. She was nominated three times for the Nobel Prize in Chemistry.

Ida Tacke was born in Wesel, Lackhausen 1896. She was one of the first women in Germany to study chemistry. She attained a doctorate in 1921 at the Technical University of Berlin "On higher aliphatic fatty acid anhydrides" and worked afterwards in the field, becoming the first woman to hold a professional chemist's position in the chemical industry in Germany. She and chemist Walter Noddack were married in 1926. Both before and after their marriage they worked as partners, an "Arbeitsgemeinschaft" or "work unit", but with the exception of her work at the University of Strasbourg, her positions were unpaid appointments.

Noddack correctly criticized Enrico Fermi's chemical proofs in his 1934 neutron bombardment experiments, from which he postulated that transuranic elements might have been produced, and which was widely accepted for a few years. Her paper, "On Element 93" suggested a number of possibilities, centering around Fermi's failure to chemically eliminate all lighter than uranium elements in his proofs, rather than only down to lead. The paper is considered historically significant today not simply because she correctly pointed out the flaw in Fermi's chemical proof but because she suggested the possibility that "it is conceivable that the nucleus breaks up into several large fragments, which would of course be isotopes of known elements but would not be neighbors of the irradiated element." In so doing she presaged what would become known a few years later as nuclear fission. However Noddack offered no experimental proof or theoretical basis for this possibility, which defied the understanding at the time. The paper was generally ignored.

Later experiments along a similar line to Fermi's, by Irène Joliot-Curie, and Pavle Savic in 1938 raised what they called "interpretational difficulties" when the supposed transuranics exhibited the properties of rare earths rather than those of adjacent elements. Ultimately on December 17, 1938, Otto Hahn and Fritz Strassmann provided chemical proof that the previously presumed transuranic elements were isotopes of barium, and Hahn wrote these exciting results to his exiled colleague Lise Meitner, explaining the process as a 'bursting' of the uranium nucleus into lighter elements. It remained for Meitner who had been forced to flee Germany in July 1938 and her exiled nephew Otto Frisch utilizing Fritz Kalckar and Niels Bohr's liquid drop hypothesis (first proposed by George Gamow in 1935) to provide a first theoretical model and mathematical proof of what Frisch named nuclear fission (he coined this term). (Frisch also experimentally verified the fission reaction by means of a cloud chamber, confirming the energy release). Ida and her husband-to-be looked for the then still unknown elements 43 and 75 at the Physikalisch-Technische Reichsanstalt.

In 1925, they published a paper (Zwei neue Elemente der Mangangruppe, Chemischer Teil) claiming to have done so, and called the new elements Rhenium (75) and Masurium (43). Only the discovery of rhenium was confirmed. They were unable to isolate element 43 and their results were not reproducible. Their choice of the term masurium was also considered unacceptably nationalistic and may have contributed to a poor reputation amongst scientists of the day. Artificially produced element 43 was definitively isolated in 1937 by Emilio Segre and Carlo Perrier from a discarded piece of molybdenum foil from a cyclotron which had undergone beta decay. It was eventually named technetium due to its artificial source. No isotope of technetium has a half-life longer than 4.2 million years and was presumed to have disappeared on Earth as a naturally occurring element. In 1961 minute amounts of technetium in pitchblende produced from spontaneous 238U fission were discovered by B.T. Kenna and Paul K. Kuroda. Based on this discovery, Belgian physicist Pieter van Assche constructed an analysis of their data to show that the detection limit of Noddacks' analytical method could have been 1000 times lower than the 10-9 value reported in their paper, in order to show the Noddacks could have been the first to find measurable amounts of element 43, as the ores they had analyzed contained uranium. Using Van Assche's estimates of the Noddacks' residue compositions, NIST scientist John T. Armstrong, simulated the original X-ray spectrum with a computer, and claimed that the results were "surprisingly close to their published spectrum!" Gunter Herrmann from the University of Mainz examined van Assche's arguments, and concluded they were developed ad hoc, and forced to a predetermined result. F. Habashi pointed out that uranium was never more than about 5% in Noddacks' columbite samples. Such a low quantity could not be weighed, nor give X-ray lines of element 43 clearly distinguishable from the background noise. The only way to detect its presence is to carry out radioactive measurements, a technique the Noddacks did not use, but Segrè and Perrier did. Following on the van Assche and Armstrong claims, an investigation was made into the works of Masataka Ogawa who had made a prior claim to the Noddacks. In 1908 he claimed to have isolated element 43, calling it Nipponium. Using an original plate (not a simulation), Kenji Yoshihara determined Ogawa had not found the Period 5 Group 7 element 43 (eka-manganese), but had successfully separated Period 6 Group 7 element 75 (dvi-manganese) (rhenium), preceding the Noddacks by 17 years.

Source: Wikipedia

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Science makes people reach selflessly for truth and objectivity.


20th century

Fields: Physics

Born: 1878 in Vienna (Austria)
Death: 1968 in Cambridge (England)

Main achievements: Discovered nuclear fission. First woman in Germany to assume a post of full professor in physics.

Lise Meitner was an Austrian physicist who worked on radioactivity and nuclear physics. Meitner was part of the team that discovered nuclear fission, an achievement for which her colleague Otto Hahn was awarded the Nobel Prize. Meitner is often mentioned as one of the most glaring examples of women's scientific achievement overlooked by the Nobel committee. A 1997 Physics Today study concluded that Meitner's omission was "a rare instance in which personal negative opinions apparently led to the exclusion of a deserving scientist" from the Nobel. Element 109, meitnerium, is named in her honour.

Meitner was born into a Jewish family as the third of eight children in Vienna, 2nd district (Leopoldstadt). Her father, Philipp Meitner, was one of the first Jewish lawyers in Austria. Meitner studied physics and became the second woman to obtain a doctoral degree in physics at the University of Vienna in 1905 ("Wärmeleitung im inhomogenen Körper"). Women were not allowed to attend public institutions of higher education in those days, but Meitner was able to achieve a private education in physics in part because of her supportive parents, and she completed in 1901 with an "externe Matura" examination at the Akademisches Gymnasium.

In 1926, Meitner became the first woman in Germany to assume a post of full professor in physics, at the University of Berlin. There she undertook the research program in nuclear physics which eventually led to her co-discovery of nuclear fission in 1939, after she had left Berlin. She was praised by Albert Einstein as the "German Marie Curie". In 1930, Meitner taught a seminar on nuclear physics and chemistry with Leó Szilárd. With the discovery of the neutron in the early 1930s, speculation arose in the scientific community that it might be possible to create elements heavier than uranium (atomic number 92) in the laboratory. A scientific race began between Ernest Rutherford in Britain, Irène Joliot-Curie in France, Enrico Fermi in Italy, and the Meitner–Hahn team in Berlin. At the time, all concerned believed that this was abstract research for the probable honour of a Nobel prize. None suspected that this research would culminate in nuclear weapons.

Following the doctoral degree, she rejected an offer to work in a gas lamp factory. Encouraged by her father and backed by his financial support, she went to Berlin. Max Planck allowed her to attend his lectures, an unusual gesture by Planck, who until then had rejected any women wanting to attend his lectures. After one year, Meitner became Planck's assistant. During the first years she worked together with chemist Otto Hahn and discovered with him several new isotopes. In 1909 she presented two papers on beta-radiation. In 1912 the research group Hahn–Meitner moved to the newly founded Kaiser-Wilhelm-Institut (KWI) in Berlin-Dahlem, south west in Berlin. She worked without salary as a "guest" in Hahn's department of Radiochemistry. It was not until 1913, at 35 years old and following an offer to go to Prague as associate professor, that she got a permanent position at KWI. In the first part of World War I, she served as a nurse handling X-ray equipment. She returned to Berlin and her research in 1916, but not without inner struggle. She felt in a way ashamed of wanting to continue her research efforts when thinking about the pain and suffering of the victims of war and their medical and emotional needs. In 1917, she and Hahn discovered the first long-lived isotope of the element protactinium, for which she was awarded the Leibniz Medal by the Berlin Academy of Sciences. That year, Meitner was given her own physics section at the Kaiser Wilhelm Institute for Chemistry. In 1922, she discovered the cause, known as the Auger effect, of the emission from surfaces of electrons with 'signature' energies. The effect is named for Pierre Victor Auger, a French scientist who independently discovered the effect in 1923.

When Adolf Hitler came to power in 1933, Meitner was acting director of the Institute for Chemistry. Although she was protected by her Austrian citizenship, all other Jewish scientists, including her nephew Otto Frisch, Fritz Haber, Leó Szilárd and many other eminent figures, were dismissed or forced to resign from their posts. Most of them emigrated from Germany. Her response was to say nothing and bury herself in her work. In 1938, Meitner fled to Holland and finally arrived in Sweden. She later acknowledged, in 1946, that "It was not only stupid but also very wrong that I did not leave at once."

After the Anschluss, her situation became desperate. On July 13, 1938, Meitner, with the support of Otto Hahn and the help from the Dutch physicists Dirk Coster and Adriaan Fokker, escaped to the Netherlands. She was forced to travel under cover to the Dutch border, where Coster persuaded German immigration officers that she had permission to travel to the Netherlands. She reached safety, though without her possessions. Meitner later said that she left Germany forever with 10 marks in her purse. Before she left, Otto Hahn had given her a diamond ring he had inherited from his mother: this was to be used to bribe the frontier guards if required. It was not required, and Meitner's nephew's wife later wore it. Meitner was lucky to escape, as Kurt Hess, a chemist who was the head of the organic department of the KWI and an avid Nazi, had informed the authorities that she was about to flee. An appointment at the University of Groningen did not come through, and she went instead to Stockholm, where she took up a post at Manne Siegbahn's laboratory, despite the difficulty caused by Siegbahn's prejudice against women in science. Here she established a working relationship with Niels Bohr, who travelled regularly between Copenhagen and Stockholm. She continued to correspond with Hahn and other German scientists. On occasion of a lecture by Hahn in Bohr's Institute he, Meitner and Frisch met in Copenhagen on November 10. Later they exchanged a series of letters. In December Hahn and Fritz Strassmann performed the difficult experiments which isolated the evidence for nuclear fission at their laboratory in Berlin. The surviving correspondence shows that Hahn recognized that fission was the only explanation for the barium (at first he named the process a 'bursting' of the uranium), but, baffled by this remarkable conclusion, he wrote to Meitner. The possibility that uranium nuclei might break up under neutron bombardment had been suggested years before, notably by Ida Tacke Noddack in 1934. However, by employing the existing "liquid-drop" model of the nucleus, Meitner and Frisch were the first to articulate a theory of how the nucleus of an atom could be split into smaller parts: uranium nuclei had split to form barium and krypton, accompanied by the ejection of several neutrons and a large amount of energy (the latter two products accounting for the loss in mass). She and Frisch had discovered the reason that no stable elements beyond uranium (in atomic number) existed naturally; the electrical repulsion of so many protons overcame the strong nuclear force. Frisch and Meitner also first realized that Einstein's famous equation, E = mc2, explained the source of the tremendous releases of energy in nuclear fission, by the conversion of rest mass into kinetic energy, popularly described as the conversion of mass into energy. Hahn and Strassmann had sent the manuscript of their first paper to Naturwissenschaften in December 1938, reporting they had detected and identified the element barium after bombarding uranium with neutrons; simultaneously, Hahn had communicated their results exclusively to Meitner in several letters, and did not inform the physicists in his own institute.

In their second publication on the evidence of barium (Die Naturwissenschaften, 10 February 1939) Hahn and Strassmann used for the first time the name Uranspaltung (Uranium fission) and predicted the existence and liberation of additional neutrons during the fission process (which was proved later to be a chain reaction by Frédéric Joliot and his team). Lise Meitner and her nephew Otto Frisch were the first who correctly interpreted Hahn's and Strassmann's results as being nuclear fission, a term coined by Frisch, and published their paper in Nature. Frisch confirmed this experimentally on 13 January 1939. These two reports, the first Hahn-Strassmann publication of January 6, 1939, and the Frisch-Meitner publication of February 11, 1939, had electrifying effects on the scientific community. Because there was a possibility that fission could be used as a weapon, and since the knowledge was in German hands, Leó Szilárd, Edward Teller, and Eugene Wigner jumped into action, persuading Albert Einstein, a celebrity, to write President Franklin D. Roosevelt a letter of caution. In 1940 Frisch and Rudolf Peierls produced the Frisch–Peierls memorandum, which first set out how an atomic explosion could be generated, and this ultimately led to the establishment in 1942 of the Manhattan Project. Meitner refused an offer to work on the project at Los Alamos, declaring "I will have nothing to do with a bomb!" Meitner said that Hiroshima had come as a surprise to her, and that she was "sorry that the bomb had to be invented." In Sweden, Meitner was first active at Siegbahn's Nobel Institute for Physics, and at the Swedish Defence Research Establishment (FOA) and the Royal Institute of Technology in Stockholm, where she had a laboratory and participated in research on R1, Sweden's first nuclear reactor. In 1947, a personal position was created for Meitner at the University College of Stockholm with the salary of a professor and funding from the Council for Atomic Research.

Source: Wikipedia

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...a talented researcher working in a difficult field who had achieved a worldwide reputation among biologists.


19th century

Fields: Biology, Genetics

Born: 1861 in Cavendish, Vermont (USA)
Death: 1912 in Baltimore, Maryland (USA)

Main achievements: XY sex-determination system.

Nettie Maria Stevens was an early American geneticist. In 1906, she discovered that male beetles produce two kinds of sperm, one with a large chromosome and one with a small chromosome. When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. This pattern was observed in other animals, including humans, and became known as the XY sex-determination system.

Nettie Maria Stevens was born on July 7, 1861, in Cavendish, Vermont, to Julia and Ephraim Stevens. After the death of her mother, her father remarried and the family moved to Westford, Massachusetts. She was graduated from Westford Academy in 1880.

Stevens taught high school and was a librarian. Her teaching duties included courses in physiology and zoology, as well as mathematics, Latin, and English. Her interest in zoology may have been influenced by taking a teacher training course she attended on Martha's Vineyard in the 1890s.

After teaching for three terms, she continued her education at Westfield Normal School (now Westfield State University) completing the four-year course in only two years and being graduated with the highest scores in her class.

After graduation at the top in her class, she attended Stanford University, where she received her B.A. in 1899 and her M.A. in 1900. She also completed one year of graduate work in physiology under Professor Jenkins and histology and cytology under Professor McFarland. Stevens continued her studies in cytology at Bryn Mawr College, where she obtained her Ph.D. and was influenced by the work of the previous head of the biology department, Edmund Beecher Wilson, and by that of his successor, Thomas Hunt Morgan.[5] Her work documented processes that were not researched by Wilson and she used subjects that he later would adopt along with the results of her work.

In her first year at Bryn Mawr, Stevens received a graduate scholarship in biology. The following year, she was named a President's European Fellow, and studied at the University of Würzburg, Germany. She also studied marine organisms at Helgoland and Naples Zoological Station. After receiving her Ph.D. from Bryn Mawr, Stevens was given an assistantship at the Carnegie Institute of Washington in the year 1904–1905. Several subsequent studies of germ cells in aphids appeared as a result. One paper (1905) won Stevens an award of $1,000 for the best scientific paper written by a woman. Another work, "Studies in Spermatogenesis," highlighted her entry into the increasingly promising focus of sex-determination studies and chromosomal inheritance. It was at this institute that Stevens had her sex determination work published as a report in 1905. At Bryn Mawr, Stevens focused on topics such as the regeneration in primitive multicellular organisms, the structure of single cell organisms, the development of sperm and eggs, germ cells of insects, and cell division in sea urchins and worms. In 1908, Stevens received the Alice Freeman Palmer Fellowship from the Association of Collegiate Alumnae, now the American Association of University Women. During her fellowship year, Stevens studied at the Naples Zoological Station and the University of Wurzburg, in addition to visiting laboratories throughout Europe.

Stevens was one of the first American women to be recognized for her contribution to science. Her research was completed at Bryn Mawr College. Her highest rank attained was the associate in experimental morphology (1905–1912). Using observations of insect chromosomes she discovered that, in some species, chromosomes are different among the sexes. The discovery was the first time that observable differences of chromosomes could be linked to an observable difference in physical attributes (i.e., whether an individual is male or female). This work was done in 1905. The experiments completed to determine this used a range of insects. She identified the Y chromosome in the mealworm, Tenebrio. She deduced that the chromosomal basis of sex depended on the presence or absence of the Y chromosome. She did not start her research until her thirties and completed her Ph.D. in 1903. She successfully expanded the fields of genetics, cytology, and embryology.

Stevens failed to gain a full regular university position, however, she achieved a research career at leading marine stations and laboratories. Her record of 38 publications includes several major contributions which further the emergence of ideas of chromosomal heredity. As a result of her research, Stevens provided critical evidence for Mendelian and chromosomal theories of inheritance.

Stevens worked to be able to become a full researcher at Bryn Mawr, however, before she could take the research professorship offered to her, she died on May 4, 1912, of breast cancer at Johns Hopkins Hospital.

Following her death, Thomas Hunt Morgan wrote an extensive obituary for the journal Science. In an earlier letter of recommendation he wrote, "Of the graduate students that I have had during the last twelve years I have had no one that was as capable and independent in research as Miss Stevens."

Studying egg tissue and fertilization process, Stevens was the first to recognize that females have two large sex chromosomes in the shape of Xs and that males have one of full size X and another that is missing a portion, making it resemble a Y. Wilson performed tests only on the testes as eggs were too fatty for his staining procedures. After her discoveries, Wilson reissued his original paper and acknowledged Stevens for this finding.

Stevens at Bryn Mawr was breeding Drosophila melanogaster in the laboratory as subjects of her research some years before Morgan adopted it as his model organism.

At 50 years old, and only 9 years after completing her Ph.D., Stevens died of breast cancer on May 4, 1912 in Baltimore, Maryland. Her career span was short, but she published approximately 40 papers. Nettie Maria Stevens was buried in the Westford, Massachusetts, cemetery alongside the graves of her father, Ephraim, and her sister, Emma.

Source: Wikipedia

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